elysium-chain-mcp

Simulate call

simulate_call

Read-onlyIdempotent

Dry-run a transaction with eth_call to estimate gas and detect reverts before sending. Provide raw data or ABI+function+args for automatic encoding and decoding.

Instructions

Dry-run a transaction with eth_call and estimate its gas, without sending anything. Provide either raw data, or abi + functionName + args to have the call data encoded and the result decoded. A transaction that would fail returns success: false with the revert reason; that is a result, not a tool error.

Input Schema

TableJSON Schema

Name	Required	Description
`to`	Yes	Recipient or contract address. 0x followed by 40 hex characters.
`abi`	No	ABI containing the function to call. Either a JSON ABI (array of items, or a single item), or human-readable signatures such as ["function balanceOf(address owner) view returns (uint256)", "event Transfer(address indexed from, address indexed to, uint256 value)"].
`args`	No	Function arguments in order. Integers may be numbers or decimal/0x-hex strings (use strings above 2^53). Tuples may be arrays or objects keyed by component name.
`data`	No	Raw call data (0x-hex). Use this or abi + functionName.
`from`	No	Sender to simulate as. Defaults to the zero address. Set it when the call depends on msg.sender or balance. 0x followed by 40 hex characters.
`block`	No	Block state to simulate against. Defaults to latest. An integer block number or a tag: latest, safe, finalized, earliest, pending.
`value`	No	HYPE to send, in wei (1 HYPE = 10^18 wei), as a decimal or 0x-hex string. Defaults to 0.
`functionName`	No	Function to call. Requires abi.

Output Schema

TableJSON Schema

Name	Required	Description
`error`	No	Node error message if the call failed for a reason other than a revert (e.g. insufficient funds).
`revert`	No	Why the call would fail, if it reverted.
`success`	Yes
`gasPrice`	Yes
`signature`	No
`returnData`	Yes	Raw return data from eth_call, if it succeeded.
`gasEstimate`	Yes	Gas units from eth_estimateGas; includes the parent-chain data cost on Arbitrum chains.
`estimatedFee`	Yes	gasEstimate × current gas price. An estimate, not a guarantee.
`decodedResult`	No	Decoded return value, when abi + functionName were given.
`gasEstimateError`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.1Oct 2, 2026

TDQS

A3.9/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond that: it is a dry run that sends nothing, it estimates gas, and a failing transaction returns success:false with the revert reason rather than a tool error. That failure-mode disclosure is valuable and not present in the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with the core action ('Dry-run a transaction ... without sending anything'). Every sentence carries information: scope, input modes, failure semantics. No filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, the description does not need to explain return values, and it already covers the critical non-obvious return behavior for reverts. Annotations cover the safety profile. The one omission is routing relative to similar sibling tools like read_contract, which would help an agent pick correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3; the individual params are already well documented. The description adds orchestration semantics the schema can't express cleanly: the two mutually exclusive input modes (raw data vs. abi + functionName + args) and the fact that the latter causes encoding and result decoding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: dry-run a transaction with eth_call, estimate gas, and do not send. This is far more precise than a tautology, and the no-send scope distinguishes it from a real transaction submission. However, it never names or contrasts with the similar sibling read_contract, so an agent must infer the boundary.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implicitly defines when to use it ('dry-run ... without sending anything') and documents the two input modes (raw data vs. abi+functionName+args). But it does not explicitly say when to choose this over read_contract or get_transaction, nor does it state any exclusions or prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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